IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-ISSN: 2278-2834,p- ISSN: 2278-8735.Volume 9, Issue 2, Ver. III (Mar - Apr. 2014), PP 19-22 www.iosrjournals.org www.iosrjournals.org 19 | Page Modeling and Simulation Using Circular Spiral Antenna Array for RF Harvesting Kang Chia Chao 1 , Mohd F.Ain 1 , Ihsan A. Zubir 1 1 School Of Electrical And Electronic Engineering, Engineering Campus, Universiti Sains Malaysia 14300 Nibong Tebal, Penang Malaysia Abstract : The design of radio frequency (RF) energy harvesting by using circular planar spiral inductor antenna arrays is proposed. The proposed antenna is a 2x1 circular spiral inductor. The size, return loss and radiation patterns were studied. It is expected that the proposed method is capable of harvesting RF electromagnetic energy more efficiently compared to when using single element spiral antenna. Both circular spiral inductors are fabricated on Roger 4003 substrates. Simulation results show that 5.14dBi gain for antenna array and 3.22dBi gain for single antenna can be achieved at frequency 527MHz. The gain has increased about 37.3% on the antenna array. Besides, practical results show that circular spiral inductor antenna array harvested more energy than a single element antenna. Therefore, the results obtained are a very attractive alternative design solution for energy harvesting system in the future. The array method of the circular spiral inductor antenna is successfully confirmed. Keywords: Antenna array, Energy harvesting, Planar spiral inductor I. INTRODUCTION In recent years, energy harvesting has been the focus of many research and development. For example, different types of source like piezoelectric, RF source or solar energy can be harvested and convert into useful DC power [1]. As the RF energy is available everywhere and anytime, this is the very reason why RF source has been very attractive. Therefore, it can either reduce or eliminate the low power integrated circuits that have wired power sources [2]. In this paper, a novel antenna array is proposed. The antenna will detect the radio frequency and will convert the electromagnetic wave into voltage response. Due to the amount of RF ambient sources been captured is extremely low, the output of the single patch antenna does not provide sufficient energy [3] to use in any application. Hence, these works were focused on design, simulate and measured of antenna array to capture electromagnetic energy from RF sources that have been radiated by the communication system in the range of 500MHz and 10GHz [4]. The momentum simulation method in ADS2008 was used to simulate and design for single element and antenna array [5]. II. MATERIAL AND METHOD OF DESIGN This section presents the material and design method of using 2x1 array circular planar spiral inductor that will use to harvest RF power. The PCB board used in this design is Duroid 4003 from Roger corps with the dielectric constant ε r = 3.38, loss tangent of 0.0027, thickness of the ground layer is 0.035mm and the parameter of the circular spiral inductor is given in Table 1. The proposed antenna array was excited by 50 ohm microstrip feeder. Table 1: Parameter of Spiral Inductor Parameter Value No. of Turn, N 10.5 Width, W 2 mm Spacing, S 0.5 mm Inner Diameter, Din 2.4 mm